get 'script.js' do
  babel :script
end

gem "sinatra", "~> 1.4.7"
gem "sinatra-contrib", "~> 1.4.7"
gem "slim", "~> 3.0.7"
gem "sass", "~> 3.4.22"
gem "babel-transpiler", "~> 0.7.0"

# coding: utf-8
require 'sinatra'
require 'sinatra/reloader'
require 'slim'
require 'sass'
require 'tilt/babel'

helpers do
  def babel(*args) render(:babel, *args) end
end

get '/style/main' do sass :'style/main' end
get '/script/main' do babel :'script/main' end

alert('test')

"xEF" on US-ASCII

No such file or directory @ rb_sysopen - /var/www/vhosts/test-project/views/script/main.babel